Preheat oven to 425F.
Line a large sheet pan with parchment paper or foil; set aside.
Cut up the potatoes, Brussel sprouts, asparagus, carrots, and red onion, and place each in a separate corner of the prepared sheet pan. DO NOT use the cherry tomatoes, yet.
Drizzle olive oil over the veggies.
Season veggies with garlic powder, 1/2 teaspoon dried rosemary, 1/2 teaspoon dried thyme, salt, and pepper.
Place 2 chicken breasts over a large piece of parchment paper.
Rub both sides of the chicken with a bit of olive oil, and season with salt, pepper, 1/2 teaspoon rosemary, 1/2 teaspoon thyme, and half of the minced garlic.
Place a pat of butter on top of each chicken breast and tightly seal the parchment paper around the chicken breasts.
Repeat the same process with the remaining 2 chicken breasts.
Place wrapped chicken on the center of the baking pan.
Bake for 30 minutes, or until chicken is cooked through. Chicken is done when internal temperature reaches 165F.
Optionally, 10 minutes before it’s done cooking, you can also add cherry tomatoes to the sheet pan.
Remove from oven and let stand 5 minutes.
Unwrap the chicken and serve.